The server now runs every lobby's sandbox and queued games as rooms, stepped at the tick rate on one thread. Players send controls ahead of time, late ones repeat their last, and everyone in a room gets back the controls it played, its events and checksums. Games start from sandbox queues, players return when they leave, and play-again moves them to a fresh room. Protocol version 3. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>